126,855 research outputs found
Ancistrosyllis matlaensis Mandal & Deb 2018, n. sp.
No full textAncistrosyllis matlaensis n. sp. (Figs 2–4) Material examined. Holotype- PUZ-323, (Length 48 mm; width 0.6 mm; 80 chaetigers): collected from Station 3 (21°50'16.9" N, 88°39'31.7" E) in Matla river in Sundarban Estuarine System, India from 2 m depth, silty-sand, during September 2016. Paratypes- 2 specimens PUZ-357 and PUZ-358 from station number 4 (21°47'34.37" N, 88°39'1.02" E) collected December 2016, 1 PUZ-359, collected February 2017. Diagnosis. Ancistrosyllis matlaensis n. sp. is characterized by the absence of eyes, presence of two lateral antennae and absence of median antennae. Dorsal cirri from 1 st chaetiger and ventral cirri from 2 nd chaetiger. Notopodial hook from 7 th chaetiger; notopodia reduced and neuropodia truncate and straight. Description (based on Holotype). Specimen complete, with 80 segments and 48 mm long and 0.6 mm wide. Body creamy white, depressed, tapered anteriorly (Figs 2a, 3a). Prostomium broad, with two lateral antennae, median antennae absent. Eyes absent. Palps biarticulate, divergent; palpophores comparatively larger than palpostyles (Fig. 2b). Pharynx globular, soft, unarmed, with denticles (Fig. 2c) and marginal papillae absent. Peristomium fused to prostomium. Parapodia poorly developed, ovoid, truncate and papillose. Cirri present on all parapodia. Two pairs of tentacular cirri, conical, papillose and inserted laterally. Dorsal cirri present from 1 st chaetiger, ovoid, papillose, papillae minute and quadrate, slightly longer than subsequent ones. Neuropodia truncate and straight, dorsal cirri smaller than ventral ones in segments which bears both of them (i.e. from 2 nd segment onwards). Notochaetae present from chaetiger 7; a large hook above dorsal cirrus resembling barbless fish hook (Fig. 4a, b). Neurochaetae sabre shaped, with bent falcate bidentate tips (Fig. 3d), smaller neurochaetae with minute serrated blades (Fig. 4c, d). Pygidium bilobed with two lateral digitate anal cirri, covered with minute quadrate papillae (Fig. 2d). Variations in Paratypes: except for minor variation in size they are entirely identical to the holotype (Fig. 3b, c). Distribution. Ancistrosyllis matlaensis n. sp. is only known from the type locality river Matla. It represents the first record of the genus from Sundarban Estuarine System, India. Comparison. Comprehensive comparisons with all other species assigned under genus Ancistrosyllis are provided in Table 2. Ancistrosyllis matlaensis n. sp. differs from A. groenlandica, A. hartmanae, A. commensalis, A. breviceps, A. fironii, A. jonesi and A. cingulata in lacking a median antenna. A. matlaensis n. sp. is different from A. quellina, A. papillosa and A. carolinensis in showing the first appearance of notopodial hooks from 7 th chaetiger. Among all the species currently classified under Ancistrosyllis, A. matlaensis n. sp. is most similar to A. falcata in having the first notopodial hooked setae from chaetiger 7. However, A. matlaensis n. sp. differs from A. falcata in lacking eyes (vs. presence of eyes in A. falcata). These two species also differ in the shape of their tentacular cirri, conical and fusiform in A. matlaensis n. sp. and A. falcata respectively. Furthermore, ventral cirri are larger than the dorsal ones in the new species and start from the second segment whereas in A. falcata the character state is exactly opposite—ventral cirri are smaller than dorsal ones and starts from first segment. Neuropodia truncate and straight in new species but truncate, bent and downwards in A. falcata (Table 2). The neurochaetae of A. matlaensis n. sp. are similar, but vary in length and shape (curved serrated cutting edges and bidentate tips); whereas in other species of Ancistrosyllis neurochaetae are of varying length, where the shorter ones are limbate, poorly spiny or indented and the longer capillaries are narrow and smooth. Ecological notes. Ancistrosyllis matlaensis n. sp. lives in silty-sand at depth of 2 m, in a salinity of 16.68 PSU. One important abiotic variable, salinity, is quite different between the A. matlaensis n. sp. and A. falcata —which the former closely resembles. The new species has been recorded from 16.68 PSU (the average annual salinity of the two collecting stations are 21.68 PSU [M3] and 20.91 PSU [M4]) and A. falcata has usually been recorded in waters with salinity 28-38.6 PSU (Bogdanos & Satsmadjis 1983, Bogdanos & Satsmadjis 1987 and Nicolaidou & Papadopoulou 1989); (Day [1957] did not provide ecological data for the type locality but at Inhaca Island which is the type locality of A. falcata the salinity is usually much higher than the new species collection locality [Macnae & Kalk 1962]). Etymology. This species is being named after the river Matla, one of the largest river of Sundarban Estuarine System. Conclusion. Ancistrosyllis matlaensis n. sp. is described from the Indian waters and contributes to the knowledge about the morphological features and its relation to various ecological factors of this species. This report will contribute to the polychaete checklist of Indian waters. As has also been said above there are important morphological and ecological differences between the new species and A. falcata which proves that the present species is a different evolutionary lineage. Hence, it is a different species according to General Lineage Concept (Queiroz 1998).Published as part of Mandal, Sumit & Deb, Soumya, 2018, Ancistrosyllis matlaensis n. sp. (Polychaeta: Pilargidae) from the Sundarban Estuarine System, India, pp. 419-429 in Zootaxa 4531 (3) on pages 422-423, DOI: 10.11646/zootaxa.4531.3.6, http://zenodo.org/record/261476
Micro-machinability of A-286 Steel with and without Laser Assist
No full textAbstractMachinability of high nickel content steels (e.g. stainless) is known to be challenging. This paper presents an experimental study of the micro-machinability of A-286 (∼43 HRC), a precipitation-hardened high nickel content steel. Micro milling experiments are carried out under dry, wet, and laser-assisted conditions, and the resulting surface morphology, burr, part feature depth, tool wear, and cutting forces are analyzed. It is found that laser-assist consistently yields the best results characterized by minimal chip adhesion to the workpiece surface, low cutting forces, good feature depth accuracy, low tool wear, and acceptable burrs
Ancistrosyllis matlaensis n. sp. (Polychaeta: Pilargidae) from the Sundarban Estuarine System, India
No full textMandal, Sumit, Deb, Soumya (2018): Ancistrosyllis matlaensis n. sp. (Polychaeta: Pilargidae) from the Sundarban Estuarine System, India. Zootaxa 4531 (3): 419-429, DOI: 10.11646/zootaxa.4531.3.
Use of pyrite microfabric as a key to tectonothermal evolution of massive sulfide deposits - an example from Deri, southern Rajasthan, India.
No full textDynamic Prioritization of Software Requirements for Incremental Software Development
No full textRequirements keep changing within an evolving business environment. In incremental software development, where functionalities are identified and delivered incrementally, a need is felt toward capturing and analyzing the impact of the changes in the system development process. This may require refactoring the order of the development of the system components based on newly added dependencies and conflicts among functional and non-functional requirements. In this paper, we propose a dynamic framework that re-prioritizes the requirements based on newly added (and updated) requirement dependencies and conflicts. We also provide an effective tool for our framework that supports software developers during incremental delivery within a changing business environment
Requirement-oriented risk management for incremental software development
No full textIn incremental software development (ISD) functionalities are delivered incrementally and requirements keep on evolving across iterations. The requirements evolution involves the addition of new dependencies and conflicts among functional and non-functional requirements along with changes in priorities and dependency weights. This, in turn, demands refactoring the order of development of system components to minimize the impact of these changes. Neglecting the non-functional constraints in the software development process exposes it to risks that may accumulate across several iterations. In this research work, we propose a risk management framework for ISD processes that provides an estimate of risk exposure for the project when functional features are frozen while ignoring the associations with non-functional requirements. Our framework proposes suitable risk reduction strategies that work in tandem with the risk assessment module. We also provide a tool interface for our risk management framework
Driving the Technology Value Stream by Analyzing App Reviews
No full textAn emerging feature of mobile application software is the need to quickly produce new versions to solve problems that emerged in previous versions. This helps adapt to changing user needs and preferences. In a continuous software development process, the user reviews collected by the apps themselves can play a crucial role to detect which components need to be reworked. This paper proposes a novel framework that enables software companies to drive their technology value stream based on the feedback (or reviews) provided by the end-users of an application. The proposed end-to-end framework exploits different Natural Language Processing (NLP) tasks to best understand the needs and goals of the end users. We also provide a thorough and in-depth analysis of the framework, the performance of each of the modules, and the overall contribution in driving the technology value stream. An analysis of reviews with sixteen popular Android Play Store applications from various genres over a long period of time provides encouraging evidence of the effectiveness of the proposed approach
Generation of Safety and Liveness Complaint Automata from Goal Model Specifications
No full textOne of the main limitations of the goal model approach to formal requirement specification is the lack of representation of temporal constraints. Existing works in this domain have transformed goal models into state machines with the only motive of model checking them against temporal properties. The generated state machines could contain invalid state sequences that violate some property. In this paper, we aim to go one step further and generate a Kripke Transition System which is compliant with respect to a given set of temporal properties. We introduce the Safety and Liveness Compliance (SLC) framework which incorporates a compliance assurance mechanism within the model transformation process itself. This assurance mechanism ensures that the generated Kripke Transition System does not generate any counter-examples when checked against the predefined safety and liveness properties. We also present a qualitative comparison of our proposed SLC framework with the other related works
NFR-aware prioritization of software requirements
No full textNon-functional requirements (NFRs) play a significant role in the software development process. However, the classical requirement prioritization methods for incremental software development, typically, consider the attributes of functional features only, often neglecting the non-functional constraints. This might lead to catastrophic defects in the system design, as the conflicts among the NFRs are ignored. In this paper, a novel prioritization approach for functional requirements (FRs) is introduced within the incremental software development process. The proposed approach considers the conflicts among NFRs, in the prioritization process, to minimize the incon sistencies of software development. The devised NFR-aware prioritization algorithm can be tuned according to the weights that the analyst assigns to NFR conflicts and FR-NFR dependencies. We have assessed our prioritization approach using available requirements data sets and have compared the results in different scenarios
Minimising conflicts among run-time non-functional requirements within DevOps
No full textSignificant contributions in the existing literature highlight the potential of softgoal interdependency graphs towards analyzing conflicting non-functional requirements (NFRs). However, such analysis is often at a very abstract level and does not quite consider the run-time performance statistics of NFR operationalizations. On the contrary, some initial empirical evaluations demonstrate the importance of the run-time statistics. In this paper, a framework is proposed that uses these statistics and combines the same with NFR priorities for computing the impact of NFR conflicts. The proposed framework is capable of identifying the best possible set of NFR operationalizations that minimizes the impact of conflicting NFRs. A detailed space analysis of the solution framework helps proving the efficiency of the proposed pruning mechanism in terms of better space management. Furthermore, a Dynamic Bayesian Network (DBN) - based system behavioral model that works on top of the proposed framework, is defined and analyzed. An appropriate tool prototype for the framework is implemented as part of this research
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